Automatic device associated with a to-size cutter for collecting abrasive or other kind of sheets

ABSTRACT

Mechanism for automatically collecting abrasive sheets, delivered by a size cutter, into reams including a conveyor, an auxiliary mobile table arranged beneath the advancement surface of the conveyor and a main mobile table arranged beneath the auxiliary table.

United States Patent Pietro Molla [72] Inventor Milan, Italy [21] Appl. No. 651,927

[22] Filed July 7, 1967 [45] Patented Jan. 26, 1971 [73] Assignee S. A. F. F. A.-Societa Per Azioni Fabbriche Fiammiferi ed Affiui Milan, Italy a corporation of Italy [32] Priority July 16, 1966 [3 3] Italy [54] AUTOMATIC DEVICE ASSOCIATED WITH A TO- SIZE CUTTER FOR COLLECTING ABRASIVE OR 7 OTHER KIND OF SHEETS 1 Claim, 11 Drawing Figs.

[52] US. Cl 93/93, 271/68 [51] Int. Cl B65h 33/00 [50] Field of Search 93/933; 27 I [68 [56] References Cited UNITED STATES PATENTS 3,027,817 4/1962 Loeffler 93/93B 3,120,384 2/1964 Fux 27'1/68 3,150,578 9/1964 Dale et al 93/93 3,159,398 12/1964 Buccicone 271/68 3,321,202 5/1967 Martin 271/68 Primary ExaminerBemard Stickney Attorney--Scrivener, Parker, Scrivener and Clarke ABSTRACT: Mechanism for automatically collecting abrasive sheets, delivered by a size cutter, into reams including a conveyor, an auxiliary mobile table arranged beneath the advancement surface of the conveyor and a main mobile table arranged beneath the auxiliary table.

FIG!

PATENIEDJMG ml vsum- 1 oi -5i;

PIETRO MOLLA INVENTOR,

P ATENT ED JAN 2 I97I SHEET 3 BF 5 INVEN'I'OR.

PIETRO MOLLA PATENIEI] mes I97! sum u or 5 INVEN'I'UR.

PIETRO MOLLA Since this sheet cc'rllect'ing and packing operation: isper;

formed manually, it requires high: la'bour rcost and, owing, to the nature of the material to be handled, a very tiresome labour. Ther'itanualopeiation becomes fstill moreonerous when operating aduplex-typ' cutter, iae. with a production of two sheets at each revolution of the transverse blade.

It is an object' of'this: invention to provide a device which, being mechanically coupled to a to-size cutter, permits the above-mentioned operation of collecting sheets into reams to be performed ina'complet'ely automatic manner and at high operation rateswhich are not possible with a manual operation. Moreparticularly, the device according to the invention is characterized in that is comprises a conveyor device for conveying the individual abrasive'sheets from the cr tter output to the collecting station of the sheets into reams, an auxiliary mobile table arranged beneath the' advancement surface of the conveyor device'and provided with an intermittent reciprocating movementfrorn inoperative position'to 'a collecting position of the sheets dischargedfrom the conveyor device, a main mobile table arranged beneath the auxiliary mobile table and also'provided with a reciprocating intermittent movement from an inoperative position to a collecting position of the sheets discharged from the conveyor device, the movements of the two mobiletabie's' being timed in such a manner that each mobile table effects its movementsfrom thein'operative position to the collecting position and vice versa while the other mobile table is in the collecting positionand the dwell FIG. 3 is a diagrammatic detailed view ofthe devices collecting the sheets into reams and. discharging them in the working; table of the machine;

' FIG. 41isa diagrammatic view, crosswise of the machine, of the electromechanicala device effecting the coupling of the teams by overlapping td a half each ream pair for the subsequent packing;

FIG. 5 is a diagrammatic longitudinal elevational view of the chain systemfor the intermittent forward movement of the -packages;

FIG; 6 is a diagrammatic planview of FIG. 5 illustrating the whole, chain'syst'em for the intermittent forward movement of the-packages;

time of the main table in the collecting position is a multiple of the dwell time of the'auxiliary table in suchposition, and a device for conveying the abrasive sheet reams away from the collecting position of the sheets into reams" having the ream advancement tablearranged beneath the main mobile table and facing it in its initial section. v

According to a feature of this invention the device for collecting the sheets into reams is coupled to a device for coupling the reams by partially'overlapping' each other and to a device for forming the packages by alternately folding back the ream edges.

It is thus provided a unit which lends itself to coupling both to a roll-fed cutter and a cutter directly connected to the flexible abrasive material manufacturing plant, thus providing a continuous operation up to the final packing. This is a requirement much sought and never met upto now in the flexible abrasive techniques. p g a The advantages deriving from the device according to this invention are: elimination of labour for collecting and packing, increased production because ofthe use of the maximum cutter speed, accuracy in sheet sound better quality and evenness of the finished packages owing to the higher evenness in the coupling and, ream folding operation. t

The invention will be better understood from the following detailed description, given byway of example only and thereto the accompanying drawings, in which: 3

" F1657 isa detailed view of a catch as seen along section CC of FIG. 5, illustrating the functional relationship between the catch, the chain and, the slide plate illustrated in FIG. 5;

FIG. 8 is a diagrammatic sectional view of the machine taken along line AA of FIG. 1, illustrating the package edge folding and package holding'mechanismsduring folding; and

FIG. 9 is a sectional view taken along line BB of FIG. 8, for further illustrating" the package holding device and the arrangement of the four holding pressers.

1 Referring to FIGS. .1 and 2, a-designates the individual sheets moving forward along the-discharge path 1 of a cutter 2, guided by suitable means of normal use on cutters of this type or on other similar machines. The sheets are arranged with the rough face facing upwards.

One of the objects of the invention is to collect these sheets into reams having a predetermined number of sheets, for example l'O, on the collecting table 3 of the machine and in addition to separate these reams so that one ream of each pair overlaps the other to a half for the subsequent packing. Obviously, due to the high rate (for instance, 100 sheets per minute) at which the cutter has to operate for an inexpensive operation, particularly if it is connecteddirectly to the abrasive material production plant, it is not possible any mechanical movement for shifting the first ream of sheets collected on the table of the machine in the short time between the arrival of two adjacent sheets. Even theintroduction of an additional table for collecting thesheets into reams does not solve the problem, since the short time elapsing between two adjacent sheets does not leave sufficient time for discharging the collectedream before continuing the operation with the next ream. An noteven' the introduction of two mutually acting collecting tables for. collecting each of the two reams individually on each table is possible, always for the reason'that theshort time between two adjacent sheets is not sufficientfor permitting the two tables to discharge the ream and return into position.

It is a basic feature of this invention to use an auxiliary mobile table 4 for the purpose of collecting the first sheet of each ream and a main mobile table 5 for collecting the reams which are mechanically interlocked and move intimed relationship ream, gives time to the main ream collecting table 5 to retract convenience in the fonn of a three-tine fork, slidesin the FIG. 1 is a diagrammatic view of the'rnachine in long'tudinal elevation, illustrating the various operational steps;

FIG. 1a in fragmentary view, to an increased-scale, of a detailofFIG.l;

FIG. Z'is a diagrammatic top plan view of the machine of F1091;

FIG. 2a is a fragmentary view, to an increased scale, of a detail of FIG. 2;

for discharging the complete ream on the machine table 3 before resuming the collection of the next sheet ream.

This basic feature of the invention is illustrated with further details in an embodiment thereof iii FIG. 3, wherein it is clearly seen the timed relationship in the mechanical movement of the two mobile tables 4 and 5.

The auxiliary table 4, which as seen inFIG. 2a is shaped for guide 6 and is pivoted to thelever 7, which is pivoted at 8 and is steadily biased by the tension spring 9 against the end of the lever 10 by means of the abutment pin 1 l. The lever 7,in addition, is pivoted to the lever pair I2, which, through the follower 13, is driven by the eccentric 14 carried by the driving shaft 15 driven directly (with a 1:1 ratio) from the main drive of the cutter. when because of the timed movement of the cam 16 (rotatable with a l:l0 ratio with respect to the cutter shaft) the lever I0 disengages the abutment 11, the lever7 due sheet arrives.

At the return of the auxiliary table 4 to the retracted rest position, the sheet collected by it is held by the wall 17 which is provided to this end with suitable openings for the flush passage of the forks of the tables 4 and 5, and drops on the ream collecting table 5 which, normally, is in its advanced operating position.

The collecting table 5, while shaped in the form of a fork with three or more tines, dwells in this position until a complete collection of the remaining sheets of each ream, i.e., in the described embodiment, until the remaining nine sheets have dropped. In the time between the last sheet of the ream and the first sheet of the next ream, the auxiliary table 4 jerks due to the described mechanisms into the position'4' for collecting the first sheet of the next ream. During this time the table 5 retracts beneath the sheet sliding table 1, whereas the sheet ream b is held by the wall 17 and dropped on the machine table 3. Immediately thereafter the table 5 moves to its operating position and collects from the table 4 (now returning to its rest position) the first sheet of the next ream and then the second sheet and the remaining sheets arriving from the cutter.

The table 5, like the table 4, in the embodiment illustrated is connected to a lever 18 pivoted at 8, steadily biased by the spring 19 to follow the contour of the eccentric 20--keyed to the same main shaft 15 of the cam 14-when this movement is allowed by the hook 21. As a matter of fact the lever 18 is held normally in advanced operating position (sheet collection) by the lever 22 whose hook 21 holds the pin 23 secured to the lever 18. The lever 22 is operated, through the follower 24, by the cam 25 carried by the shaft 26 which carries also the cam 16 controlling the releasing device of the auxiliary table 4. The shaft 26 receives its drive from the main shaft of the cutter with a ratio which is in a reverse proportion to the number of sheets in each ream, in this instance 1:10, so that at each revolution of the cutter-i.e. at each sheet cut-the shaft 26 and the associated earns 25 and 16 move by a tenth of a revolution.

it is apparent the importance of the function of the earns 25 and 16 inasmuch as they, through .the associated levers 22 and and the abutments 23 and 11, determine the operation times of the tables 5 and 4 and perform implicitly the operation of counting sheets. As a matter of fact the projection 27 on the contour of the cam 16 causes, at each tenth of a revolution-through the mechanisms already illustrated-the instantaneous forward movement of the auxiliary table 4 for collecting the first sheet, whereas the projection 28 on the cam 25 causes at each tenth of a revolution the instantaneous retracting movement of the table 5 for discharging the collected complete ream. For the remaining part of the revolution of the cam 16 the auxiliary table 4 remains locked in its retracted rest position, whereas for the remaining part of the revolution of the cam 25 the table 5 remains locked in position for collecting the remaining nine sheets. in other words, at each revolution of the shaft 26 corresponds the cutting and the forward movement of 10 sheets, of which one is collected initially by the table 4 and the other nine by the table 5.

Obviously, it is possible to control thetwo sheet collecting tables 4 and 5 in timed relationship by mechanical means or by means of other character difierent from those illustrated, without departing from the scope of this invention, whose essence is the function of the auxiliary table 4 and the main table 5 respectively for automatically collecting the sheets arriving from a cutter, into reams of a predetermined number of sheets, and discharging the reams for the subsequent packing.

It is also obvious that there is the possibility of changing the speed ratios of the various mechanical control components of the sheet collecting device, both to fit to different production rates of the cutter and to collect reams having a different number of sheets with respect to that of the case illustrated.

It should be also understood as falling within the scope of this invention the possibilityof collecting, for instance, more than one sheet on the auxiliary table 4 should this be made advisable by a production rate of the cutter far higher than that of sheets per minute considered in this' description, i.e. when the advancement rate of the sheets would be so high that the tables 4 and 5 are not permitted to retract and to move forward during the sequence time of a single sheet.

The following devices have proved useful for making the various collecting operations of the sheets into reams by the auxiliary table 4 and the main table 5 easier:

A sheet ejector device at the output of the table 1 for the sliding movement of the sheets from the cutter. It consists in an ejector roll 29 and a pair of rolls 30 (FIG. 3) whose purpose is to impart a speed to the sheets which is slightly higher than that they have on the sliding table 1. The roll 29 is suitably driven by the machine drive, whereas the rolls 30 are driven (FIG. 2) through a pair of driven pulleys 31 and belts 32. The action from this ejector unit is integrated by a pair of shaped guides 33 (FIGS. 2 and 3) having to purpose of suitably warping the sheet upwardly at ejection to prevent the sheetwhen leaving the table-from curving downwardly and sliding on the rough face of the 'underlying sheets-1n other words, the object of the described ejector device is to leave the sheet in such a manner that it drops accurately and entirely over the collecting tables, particularly when there are already sheets collected on the table 5, and this isaccomplished when the ejected sheet is-thrown with such a speed as to slightly strike the sheet stopping wall 34. For alignment of the ejected sheets there is in addition to the wall 34 also a sidewall 35; these walls are both provided with large openings (FIG. 1) for discharging the air cushion which builds up beneath each sheet when it drops on the sheet ream.

A vibrator device for sheet settling, consisting in the already-mentioned wall 17, through which the sheet collecting tables 4 and 5 slide, driven by a conventional mechanical or electromechanical vibrator device 36, performing the double function of settling the sheets on the table 5 and promoting the drop of the sheet ream from the table 5 to the table 3.

On the table 3 of the machine, in the range of the sheet collecting device, the ream coupling operation is performed by staggering the first of each couple of reams discharged from the mobile table 5, so as to overlap a half of each couple of reams. it should be pointed out that the benefits deriving by the provision of two independent tables for collecting the sheets into reams is taken advantage 'of also in this stage inasmuch as it is possible to effect easily the staggering of the reams without interfering with abrupt movements in collecting sheets.

The ream coupling operation is the first stage of the whole five-stage operation (FIG. 2) corresponding to five stations, namely: ream coupling, dwelling for inspection, folding of the first edge, folding of the second edge, pressing and discharge of the finished package.

The staggering (FIG. 2) is performed by a mobile plate 37, which by coming into action every 20 sheets, pushes to ream b to b. This movement takes place in the time during which the table 5 is in collecting position for the second ream. The time 12 is determined (FIG. 4) by a cam 38 carried by the main shaft 39 of the machine which, in the packing section has a ratio of 1:20 with respect to the cutter. in other words, every 20 sheets, i.e. every two reams, the cam makes one revolution and at each revolution the cam surface 40 operates a microswitch 41 which through a suitable electric circuit starts the reversible motor 42 carrying by means of the gear 44 the chain 43 which embraces as a loop crosswise the machine bed 3 with the aid for the. idler sprocket wheels 44'.

In the embodiment illustrated in the drawings, the sheet pusher plate 37 is secured to the guide, sleeve 45 slidable on the stationary shaft 46 and to the chain 43 with which is moves together. Under the pulsefrom the microswitch 41 the sheet pusher plate 37 moves forward pushing the paper ream crosswise of the machine until the sleeve 45 operates the microswitch 47 which, through another suitable electric circuit, causes the motor 42 to reverse the direction of its rotation and thus the sheet pusher plate 37 to retract to the starting position, where the sleeve 45 operates the microswitch 48 whose function is to stop the motor.

The amount of the-movement of the sheet pusher plate 37 to shift the sheet ream b to the position b isdetermined so as to achieve overlapping to a half of the sheet reams when the next ream will be discharged from the collecting table 5 on the ream b. In this manner the two reams are ready for subsequent feeding through the further packing steps.

As already stated, the packing steps-including the ream coupling-are performed in five stations, in four of which each ream pair is caused to dwell a' time corresponding to a lO-sheet sequence. Theoperationperformed in the first station has been already illustrated; in the second station the package is caused to dwell; in the third station the folding of the left edge of the'package takes place; in the fourth station the folding of the right edge of the package takes place and in the last station the pressing and the discharge of the finished package occurs.

The feeding ofthe packages from the first to the fifth station is effected(See FIG; 1) by means of the chain 49 driven by the sprocket wheel 50 in a continuous motion derived in a ration of 1:2 from the cross shaft 47 directly driven by the alreadymentioned drive shaft 39, which rotates with a 1:20 ratio with respect to the cutter sheets. In other words, the sprocket wheel 50, which drives the chain 49, performs one revolution every sheets. Since the packages in the various stations must dwell a time corresponding to 10 sheets, an intermittent advancement device illustrated in FIGS. 5, 6 and 7 has been provided.

Secured onthe chain 49 at a spacing corresponding to the spacing between the various stations are catches 51 in the form of brackets which normally travel by gravity depending from the chain 49. At the time they abut the stationary guide plate 52, they tilt upwards sliding over the plate. Constructionally, as isseen fromthe detail in FIG. 7, the plate 52 is secured to the guide 53 carrying the chain 49. When the catch 51 rides over the plate 52, it penetrates a suitable slot 54 in the table 3 of the machine and pushes by means of the projecting portion the sheet package to the next station. Each plate 52 is of such a length as to render the catch 51 operating when it has to effect the advancement of the sheets from one station to another. p

The catches 51 with the associated tilting and sliding plate 52 are mounted alternately on the left-hand side and the righthand side of the chain 49 (FIGS. 5 and 6) and are spaced, as already stated, a distance corresponding to the spacing between the various stations, which spacing is run in a time corresponding to the sequence of l0'sheets on the path of the cutter, whereas the spacing between two right-hand catches and that between two lefi-hand catches corresponds to sheets, i.e. to a package (the left-hand and right-hand position is referred to, in this description, to the advancement direction of the machine).

The alternate arrangement of the catches 51 on the righthand side and the left-hand side of the chain 49 determines therefor for each package the alternation of an advancement for a time corresponding to l0 sheets and a dwell also for the time of 10 sheets at each station. This occurs inasmuch as the package is pushed alternately by a right-hand catch and a lefthand catch, whereas the dwells are determined by the drop of the catches beneath the machine table owing to lack of righthand sliding plates in the sections where left-hand catches operate and to lack of left-hand sliding plates in the sections where right-hand catches operate.

For a regular advancement of the packages from the first to the fourth station inclusive (FIG. 6), two central advancement chains are use, substantially like that described, which are arranged at the central area where the two sheet reams are overlapped and are running lengthwise of the machine. Two more identical but shorter chains are arranged laterally and in a parallel position with respect to the central chains; one thereof extends from the first to the fourth station and serves to push the free right-hand edge, and the other extends from the first to the third station for pushing the left-hand edge, to the associated folding stations. In the embodiment illustrated the two central chains are symmetrical as to the arrangement of the right-hand and left-hand catches; the two outer chains are likewise symmetrical.

The advancement of the composite package in the first station, for instance by the right-hand catch 51 of the central right-hand chain (FIG. 6) occursin the time the table 5 collects the first ream of the next pair of reams, however with a very slight delay with respect to the timing of the sheet collecting device to compensate for the time required for discharging the reams in the first station after completing the collection of each ream. Therefore, a moment before the package reaches the second station, the discharge of the first ream from the table 5 takes place in the first station. This first ream will dwell for a time of 10 sheets in the first station, since the next lefthand catch 51 of the same chain is inoperative in this station. During this dwell the staggeringof the firstream and the collection of the second ream occurs with a discharge of the latter on the first, timely for the advancement to the second station at the arrival of the right-hand catch of the chain just considered.

The package does not undergo any mechanical operation in the second station. This is a simple dwell station and permits a possible substitution for a defective sheet, if any, by the operator. After a dwell time corresponding to 10 sheets, due to inoperation of the next right-hand catch of the same chain in this station, the package is engaged by a left-hand catch and pushed to the third station where the folding back of the lefthand edge of the package occurs. The package is thus pushed alternately by a right-hand catch and a left-hand catch of the same chain to the last station. From the fourth station, where the folding of the right-hand edge occurs, the package is pushed for the last time (FIG. 6) by catches sliding on plates 52 and in slots 54' which are longer than usual to permit the package to be brought in such a position as to be caught by the pair of discharge pulleys 81 illustrated thereinafter.

The folding of the left edge of the package is effected by a reciprocating mechanism consisting (FIG. 8) in a segment 55, on which a spring folding plate 56 is mounted, which mechanism is arranged beneath the machine table 3 and at each cycle corresponding to 20 sheets-but in a time corresponding to 10 sheets-carries out a translation movement along an are, passing through a suitable opening 83 in the machine table, for raising the edge of the ream b and folding it back over the ream b in the central overlapping portion of the reams.

Before the segment 55 with its associated folding plate 56 starts the folding operation, it is required that the package be held firmly and to this end a set of pressing members 57 is provided which are arranged on the two sides of the package in both edge folding stations. There are therefore four pressing members on a line (FIGS. 2 and 9). Each pair of pressing members 57 carries out a double vertical reciprocating up and down motion and a rotary motion about its centerline to bring itself in package holding position. In the rest position it is beneath the machine table 3 in order not to interfere with the advancement of the package. When the package comes into position, the pressing member rises vertically through a suitable opening 84 until above the depth of the stacked reams and then rotates about its centerline by to bring itself with the projecting portion above the package and thereafter descends until it exerts a holding pressure on the package. After the edge folding is finished, the pressing member rises slightly leaving the package free, rotates again about its center line by 90 until it is back in its starting position and descends beneath the machine table 3 to permit a new package to move forward.

Each pressing member 57 is operated by an identical mechanism, substantially as illustrated in FIG. 8. The pressing member 57 is secured in offcenter relationship to a pin 58 slidable in the support sleeve 59. The vertical movement of the pin 58 is imparted by the lever 60 which is hingedly mounted by means of a fork 67 and a sleeve 66 (FIG. 9) on the pin 58. The lever 60 is pivoted on the shaft 61 (FIG. 8) and operated through the follower 62 of the cam 63 mounted on the already mentioned shaft 39 which rotates with a 1:20 ratio with respect to the cutter. The force for raising the pin 58 with the pressing member 57 is exerted by the spring 64; the latter, in addition, causes the follower 62 to follow the contour of the cam 63, which determines the times of the vertical movement.

The rotational movement about its center line of the pin 58 and associated pressing member 57 is given by a rack 65, common to all four pressing members, through a ring gear 66' provided on the already-mentioned sleeve 66 slidable on the pin 58. The rack 65 is suitably operated (FIG. 9) by the lever system 68, spring 69, follower 70 and cam 71 mounted on the shaft 72, directly derived from the above-mentioned drive shaft 39.

The pressure by the pressing member 57 on the package is exerted by the spring 73 on the pin 58 between the sleeve 66 and the abutment ferrule 74, which'permits also fitting to possible depth changes in the package.

As soon as the pressing member 57 arrives in the package holding position, the segment 55 with its associated folding plate 56 (FIG. 8) starts its folding cycle of the edge of the ream'b. This movement is imparted by a gear 75 mounted fixed to the segment 55 and meshing with a rack 76. This rack is connected to a lever system 77 operated through the follower 78 by a cam 79 on the main drive shaft 39. To return the folding device to the starting position beneath the machine table 3 in order not to restrain the advancement of the next package, the rack 76 is caused to retract by the tension spring 80.

The complete cycle of the folding and sheet holding mechanisms is accomplished-as already stated-in the time corresponding to the advancement of sheets from the cutter and the times of the one are closely related to the times of the other.

' In the embodiment forming an object of this description, for reasons of a higher strength the folding plate 56 is spring mounted, at its ends, on two indentical segments 55, each provided with the various above-described mechanical components.

Another mechanism identical to that above described is used in the fourth station for folding the second edge, with the exception that the latter is shaped symmetrical with respect to the former.

After completing the folding of the second edge, the now finished package c is caused to move forward in the above described manner until it is caught by the pair of pulleys 81 with V-belts, of conventional use, for advancing the package and make easy the entry into a pair of pressing rollers 82 which are also driven and of which the upper roller is also spring mounted. These rollers perform the double function of pressing and ejecting the finished packages c from the machine.

For the sake of simplicity the embodiment described refers to a single-channel device, i.e. suitable for a cutter cutting a single sheet at each revolution of the transverse blade, but it can be also used for duplex cutters by suitably doubling symmetrically the device. lt should be moreover understood that the scope of the invention is not limited to the use of flexible abrasive sheets inasmuch as the device can also be used for any sheet material requiring the coupling and folding of the sheets in the manner described.

Generally, while'but one embodiment of the invention has been described, it is4obvious that a number of changes and modifications can be made without departing from the scope of the invention.

lclaim: 1. An automatic device adapted to be associated with a tosize cutter for collecting abrasive or other kind of sheets into reams, characterized in that it comprises a frame having a conveyor device for conveying the individual abrasive sheets from the cutter output to the collecting station of the sheets into reams, an auxiliary mobile table arranged beneath the advancement surface of the conveyor device and provided with an intennittent reciprocating movement from an inoperative position to a collecting position of the sheets discharge from the conveyor device, a main mobile table arranged beneath the auxiliary mobile table and also provided with a reciprocating intermittent movement from an inoperative position to a collecting position of the sheets discharged from the conveyor device, the movements of the two mobile tables being timed in such a manner that each mobile table effects its movements from the inoperative position to the collecting position and vice versa while the other mobile table is in the collecting position and the dwell time of the main table in the collecting position is a multiple of the dwell time of the auxiliary table in such position, and a device for conveying the abrasive sheet reams away from the collecting position of the sheets into reams, having the ream advancement table arranged beneath the main mobile table and facing it in its initial section, the auxiliary mobile table and the main mobile table being hinged each to an end of a lever which is pivoted at the opposite end at a fixed point of the frame and undergoes in an intennediate point thereof the action of an eccentric mounted on a shaft connected to the main drive of the cutter, said levers carrying each in an intermediate point an abutment for an element undergoing the action of a cam carried by a shaft having with respect to the eccentric drive shaft a reduction ratio which is in reverse proportion to the number of sheets in each ream, said cams having the function of unlocking the levers hinged to the auxiliary and main tables for leaving said tables free to be brought to a collecting position and vice versa under the action of lever return springs and the eccentrics carried by the drive shaft connected to the cutter drive, respectively. 

1. An automatic device adapted to be associated with a to-size cutter for collecting abrasive or other kind of sheets into reams, characterized in that it comprises a frame having a conveyor device for conveying the individual abrasive sheets from the cutter output to the collecting station of the sheets into reams, an auxiliary mobile table arranged beneath the advancement surface of the conveyor device and provided with an intermittent reciprocating movement from an inoperative position to a collecting position of the sheets discharge from the conveyor device, a main mobile table arranged beneath the auxiliary mobile table and also provided with a reciprocating intermittent movement from an inoperative position to a collecting position of the sheets discharged from the conveyor device, the movements of the two mobile tables being timed in such a manner that each mobile table effects its movements from the inoperative position to the collecting position and vice versa while the other mobile table is in the collecting position and the dwell time of the main table in the collecting position is a multiple of the dwell time of the auxiliary table in such position, and a device for conveying the abrasive sheet reams away from the collecting position of the sheets into reams, having the ream advancement taBle arranged beneath the main mobile table and facing it in its initial section, the auxiliary mobile table and the main mobile table being hinged each to an end of a lever which is pivoted at the opposite end at a fixed point of the frame and undergoes in an intermediate point thereof the action of an eccentric mounted on a shaft connected to the main drive of the cutter, said levers carrying each in an intermediate point an abutment for an element undergoing the action of a cam carried by a shaft having with respect to the eccentric drive shaft a reduction ratio which is in reverse proportion to the number of sheets in each ream, said cams having the function of unlocking the levers hinged to the auxiliary and main tables for leaving said tables free to be brought to a collecting position and vice versa under the action of lever return springs and the eccentrics carried by the drive shaft connected to the cutter drive, respectively. 